This invention relates to a process for production of surimi from fish infected with the parasite Ichthyophonus hoferi and to a process for production of a surimi based products using the resultant surimi as the raw material.
Production of surimi from fish meat and business of a surimi based products have become a global industry practiced all over the world. On the other hand, because of the controlled fish catch, etc., surimi have become to be produced from raw materials which were never used in production of surimi so far.
The essential process of production of surimi is as follows: Water-soluble proteins which may interfere with gel formation are removed from fish meat proteins by rinsing in water, and the skin, tendon, and bones are removed by a refiner or the like, followed by dehydration so that the gel-forming major protein, i.e., the myofibrilla protein, is concentrated. The resultant dehydrated meat is mixed with sugar, sugar alcohol, and sodium poly-phosphate that serve as agents for prevention of freeze denaturalization, and the mixture is frozen.
The basic process for production of a surimi based product utilizing the surimi comprises the steps of thawing a frozen surimi to some extent, grinding and kneading the surimi by a cutter or the like with salt added to the surimi, further adding seasonings, minor raw materials, etc., and then molding and heating the mixture. The quality of a a surimi based product is evaluated from various viewpoints, among which characteristic physical properties take a great part. Actomyosin, which is the major protein of surimi and soluted from the myofibrils in the step of grinding with salt, plays an important role in gel-formation. Although physical properties of gel of a heated fish cake(Kamaboko in Japanese) vary depending on the fish species used as raw materials, it is known that the physical properties of the boiled surimi gel are influenced by the properties of the proteins unique to the fish species and enzymes contained in the fish meat.
Many fish species are known to be useful as raw materials of surimi, including Alaska pollock (Theragra chalcogramma), pacific whiting (Merluccius productus), Atka mackerel, sardine, southern blue whiting, hoki, croaker, alfonsino, lizard fish, and Yellow fin sole (Limamda aspera). Also, there are many species of parasites that infect fish meat, but only certain species of fish and certain species of parasites are known to develop jellying of fish meat.
For example, it is known that the muscle of pacific whiting (Merluccius productus) or Yellow fin sole (Limamda aspera) is infected with Myxosporidian so that the activity of protease in the muscle is elevated and develops the jellying, i.e., the muscle is liquefied under heating. If such fish is used as the raw material for surimi, protease acts under heating for formation of the heated surimi gel to degrade the major gel proteins so that the gel cannot be formed. For prevention of this phenomenon, a technique has been developed to produce surimi using a protease inhibitor. (Japanese Patent No. 1,473,166 and U.S. Pat. No. 4,284,653)
An object of this invention is to provide a process for production of surimi with stable quality from fish infected with the parasite Ichthyophonus hoferi in fish meat.
Another object of this invention is to provide a process for production of high-quality a surimi based products using the surimi produced from fish infected with the parasite Ichthyophonus hoferi as the raw material.
The gist of this invention resides in a process for production of surimi from parasite-infected fish, wherein an additive for inhibiting protease activity and recovering gel-forming capability is added in the process of production of surimi from fish infected with the parasite Ichthyophonus hoferi. 
This invention uses a protease inhibitor as the above-mentioned additive and also calcium as needed. Thus the gist of this invention resides in a process for production of surimi from parasite-infected fish, wherein a protease inhibitor is added to inhibit protease activity and recover gel-forming capability and calcium is also added as needed in the process of production of surimi from fish infected with the parasite Ichthyophonus hoferi. 
When surimi is produced from fish infected with Ichthyophonus hoferi, the resultant surimi has a high protease activity and has a poor gel-forming capability. Based on finding of this fact, a protease inhibitor is added to inhibit the protease activity and recover the gel-forming capability. Because the main constituent of protease is thiol protease, a thiol protease inhibitor is preferably used.
Another gist of this invention resides in a process for production of a surimi based product, wherein an additive for inhibiting protease activity is added in production of a surimi based product using surimi produced from fish infected with Ichthyophonus hoferi as the raw material.
A protease inhibitor is used as the above-mentioned additive. Thus the gist of this invention resides in a process for production of a surimi based product, wherein a protease inhibitor is added to inhibit protease activity in production of a surimi based product using surimi produced from fish infected with Ichthyophonus hoferi as the raw material. Because the main constituent of protease is thiol protease, a thiol protease inhibitor is preferably used.